Navigation devices are widely used for planning routes from starting points to set destinations. For example, a navigation device is known that plans a route without taking an unnecessary detour even when a destination is not exactly determined at the point of departure (refer to Japanese Unexamined Patent Application Publication No. 2011-209027). Such a navigation device searches for a plurality of routes to provisional destinations, and requests a user to narrow down the destinations when approaching a junction of the routes.
The navigation device described in Japanese Unexamined Patent Application Publication No. 2011-209027), however, still requires the user to designate a final destination; otherwise the route guidance cannot be continued.